gld

, gld_mac_alloc

, gld_mac_free

, gld_register

, gld_unregister

, gld_recv

, gld_sched

, gld_intr

- Generic LAN Driver service routines

Synopsis

#include <sys/gld.h> 

gld_mac_info_t *gld_mac_alloc(dev_info_t *dip);

void gld_mac_free(gld_mac_info_t *macinfo);

int gld_register(dev_info_t *dip, char *name, gld_mac_info_t *macinfo);

int gld_unregister(gld_mac_info_t *macinfo);

void gld_recv(gld_mac_info_t *macinfo, mblk_t *mp);

void gld_sched(gld_mac_info_t *macinfo);

uint_t gld_intr(caddr_t);

void gld_linkstate(gld_mac_info_t *macinfo, int32_t newstate);

Interface Level

Solaris architecture specific (Solaris DDI).

Parameters

macinfo

Pointer to a gld_mac_info(9S) structure.

dip

Pointer to dev_info structure.

name

Device interface name.

mp

Pointer to a message block containing a received packet.

newstate

Media link state.

Description

gld_mac_alloc( ) allocates a new gld_mac_info(9S) structure and returns a pointer to it. Some of the GLD-private elements of the structure may be initialized before gld_mac_alloc( ) returns; all other elements are initialized to zero. The device driver must initialize some structure members, as described in gld_mac_info(9S), before passing the mac_info pointer to gld_register( ).

gld_mac_free( ) frees a gld_mac_info(9S) structure previously allocated by gld_mac_alloc( ).

gld_register( ) is called from the device driver's attach(9E) routine, and is used to link the GLD-based device driver with the GLD framework. Before calling gld_register( ) the device driver's attach(9E) routine must first use gld_mac_alloc( ) to allocate a gld_mac_info(9S) structure, and initialize several of its structure elements. See gld_mac_info(9S) for more information. A successful call to gld_register( ) performs the following actions:

• links the device-specific driver with the GLD system;

• sets the device-specific driver's private data pointer (using ddi_set_driver_private(9F)) to point to the macinfo structure;

• creates the minor device node.

The device interface name passed to gld_register( ) must exactly match the name of the driver module as it exists in the filesystem.

The driver's attach(9E) routine should return DDI_SUCCESS if gld_register( ) succeeds. If gld_register( ) returns DDI_FAILURE, the attach(9E) routine should deallocate any resources it allocated before calling gld_register( ) and then also return DDI_FAILURE.

gld_unregister( ) is called by the device driver's detach(9E) function, and if successful, performs the following tasks:

• ensures the device's interrupts are stopped, calling the driver's gldm_stop( ) routine if necessary;

• removes the minor device node;

• unlinks the device-specific driver from the GLD system.

If gld_unregister( ) returns DDI_SUCCESS, the detach(9E) routine should deallocate any data structures allocated in the attach(9E) routine, using gld_mac_free( ) to deallocate the macinfo structure, and return DDI_SUCCESS. If gld_unregister( ) returns DDI_FAILURE, the driver's detach(9E) routine must leave the device operational and return DDI_FAILURE.

gld_recv( ) is called by the driver's interrupt handler to pass a received packet upstream. The driver must construct and pass a STREAMS M_DATA message containing the raw packet. gld_recv( ) determines which STREAMS queues, if any, should receive a copy of the packet, duplicating it if necessary. It then formats a DL_UNITDATA_IND message, if required, and passes the data up all appropriate streams.

The driver should avoid holding mutex or other locks during the call to gld_recv( ). In particular, locks that could be taken by a transmit thread may not be held during a call to gld_recv( ): the interrupt thread that calls gld_recv( ) may in some cases carry out processing that includes sending an outgoing packet, resulting in a call to the driver's gldm_send( ) routine. If the gldm_send( ) routine were to try to acquire a mutex being held by the gldm_intr( ) routine at the time it calls gld_recv( ), this could result in a panic due to recursive mutex entry.

gld_sched( ) is called by the device driver to reschedule stalled outbound packets. Whenever the driver's gldm_send( ) routine has returned GLD_NORESOURCES, the driver must later call gld_sched( ) to inform the GLD framework that it should retry the packets that previously could not be sent. gld_sched( ) should be called as soon as possible after resources are again available, to ensure that GLD resumes passing outbound packets to the driver's gldm_send( ) routine in a timely way. (If the driver's gldm_stop( ) routine is called, the driver is absolved from this obligation until it later again returns GLD_NORESOURCES from its gldm_send( ) routine; however, extra calls to gld_sched( ) will not cause incorrect operation.)

gld_intr( ) is GLD's main interrupt handler. Normally it is specified as the interrupt routine in the device driver's call to ddi_add_intr(9F). The argument to the interrupt handler (specified as int_handler_arg in the call to ddi_add_intr(9F)) must be a pointer to the gld_mac_info(9S) structure. gld_intr( ) will, when appropriate, call the device driver's gldm_intr( ) function, passing that pointer to the gld_mac_info(9S) structure. However, if the driver uses a high-level interrupt, it must provide its own high-level interrupt handler, and trigger a soft interrupt from within that. In this case, gld_intr( ) may be specified as the soft interrupt handler in the call to ddi_add_softintr( ).

gld_linkstate() is called by the device driver to notify GLD of changes in the media link state. The newstate argument should be set to one of the following:

GLD_LINKSTATE_DOWN

The media link is unavailable.

GLD_LINKSTATE_UP

The media link is unavailable.

GLD_LINKSTATE_UNKNOWN

The status of the media link is unknown.

If a driver calls gld_linkstate(), it must also set the GLD_CAP_LINKSTATE bit in the gldm_capabilties field of the gld_mac_info(9S) structure.

Return Values

gld_mac_alloc( ) returns a pointer to a new gld_mac_info(9S) structure.

gld_register( ) and gld_unregister( ) return:

DDI_SUCCESS

on success.

DDI_FAILURE

on failure.

gld_intr( ) returns a value appropriate for an interrupt handler.

See Also

gld(7D), gld(9E), gld_mac_info(9S), gld_stats(9S), dlpi(7P), attach(9E), ddi_add_intr(9F).

Writing Device Drivers